异步回调

public class CompletableFutureDemo {

    public static void main(String[] args) throws Exception {
        //同步，异步，异步回调
        //MQ消息中间件
        //同步
        CompletableFuture<Void> future1 = CompletableFuture.runAsync(()->{
            System.out.println("CompletableFuture.runAsync");
        });
        future1.get();



        //异步回调
        CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync(()->{
            System.out.println("CompletableFuture.supplyAsync");
            int a = 10/0;
            return 1024;
        });

        future2.whenComplete(
                (t,u)->{
                    System.out.println("*****t="+t); //值
                    System.out.println("*****u="+u); //u是错误信息
                }
        ).exceptionally(
                f->{
                    System.out.println(f.getMessage());
                    return 444;
                }
        );

    }
}